In a large mixing bowl, add vinegar, water, honey, sea salt and peppercorns.

Whisk until well combined.

Peel, halve, then thinly slice the onions. Place them in a large mason jar, and pour in your vinegar mixture.

Cover and seal your jar, then refrigerate for at least 24 hours prior to serving.

Pickled onions will last for up to 2 weeks refrigerated.